Desulfovibrionales

Overview

Desulfovibrionales is an order of Gram-negative bacteria within the class Deltaproteobacteria. These bacteria are known for their ability to reduce sulfate to sulfide during their metabolic processes, a characteristic that is significant in the sulfur cycle. Members of this order are typically found in anaerobic environments such as sediments, soils, and the gastrointestinal tracts of animals.

Morphology

Desulfovibrio vulgaris under a microscope

Bacteria within the Desulfovibrionales order are generally rod-shaped or vibrioid, and they possess a single polar flagellum that allows for motility. The cell walls of these bacteria are thin, characteristic of Gram-negative organisms, and they do not form spores.

Metabolism

Desulfovibrionales are obligate anaerobes, meaning they thrive in environments devoid of oxygen. They utilize sulfate as a terminal electron acceptor in their energy metabolism, reducing it to hydrogen sulfide. This process is known as dissimilatory sulfate reduction. The energy derived from this process is used for growth and maintenance of cellular functions.

Ecological Role

The reduction of sulfate to sulfide by Desulfovibrionales plays a crucial role in the biogeochemical cycles of sulfur and carbon. By converting sulfate to sulfide, these bacteria contribute to the formation of sulfide minerals and influence the availability of sulfur in the environment. Additionally, the hydrogen sulfide produced can react with metals, leading to the formation of metal sulfides, which are important in ore formation.

Industrial and Environmental Impact

Desulfovibrionales can have both beneficial and detrimental effects. In wastewater treatment, they help in the degradation of organic matter under anaerobic conditions. However, the production of hydrogen sulfide can lead to corrosion of metal infrastructure and the generation of sour gas in oil and gas industries, posing challenges for maintenance and safety.

Related Pages

• Sulfate-reducing bacteria
• Deltaproteobacteria
• Anaerobic respiration
• Biogeochemical cycle